Blood Glucose Conversion
Converts blood-sugar units between countries.
Formula
Variables
Example
90 mg/dL ⇒ 5.0 mmol/L
How it works
Blood glucose can be reported in two common unit systems: milligrams per decilitre (mg/dL) and millimoles per litre (mmol/L). The number 18 is the conversion factor that links the mass-based US unit to the mole-based international unit for glucose, so dividing by 18 gives the equivalent value in mmol/L. This works because the same amount of glucose is being measured, just expressed in different unit systems.
When to use it
Use this when reading or comparing blood-sugar results from different countries, medical devices, or lab reports. It is also useful when you need to interpret diabetes targets, home glucose meter readings, or clinical guidelines written in mmol/L.
Worked example, step by step
Convert 126 mg/dL to mmol/L mmol/L = mg/dL ÷ 18 mmol/L = 126 ÷ 18 mmol/L = 7.0 Final answer: 126 mg/dL = 7.0 mmol/L
Common mistakes to avoid
- Multiplying by 18 instead of dividing by 18
- Using the formula for units other than glucose without checking the correct conversion
- Forgetting that the result is approximate when rounding to one decimal place
Did You Know?
The US reports blood sugar in mg/dL while most of the world uses mmol/L — the two differ by a factor of 18.
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